lib/kobject_uevent.c - fp2-dev/kernel/msm - Gitiles

 /*
  * kernel userspace event delivery
  *
  * Copyright (C) 2004 Red Hat, Inc.  All rights reserved.
  * Copyright (C) 2004 Novell, Inc.  All rights reserved.
  * Copyright (C) 2004 IBM, Inc. All rights reserved.
  *
  * Licensed under the GNU GPL v2.
  *
  * Authors:
  *	Robert Love		<rml@novell.com>
  *	Kay Sievers		<kay.sievers@vrfy.org>
  *	Arjan van de Ven	<arjanv@redhat.com>
  *	Greg Kroah-Hartman	<greg@kroah.com>
  */

 #include <linux/spinlock.h>
 #include <linux/socket.h>
 #include <linux/skbuff.h>
 #include <linux/netlink.h>
 #include <linux/string.h>
 #include <linux/kobject.h>
 #include <net/sock.h>

 #define BUFFER_SIZE	2048	/* buffer for the variables */
 #define NUM_ENVP	32	/* number of env pointers */

 #if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
 static DEFINE_SPINLOCK(sequence_lock);
 static struct sock *uevent_sock;

 static char *action_to_string(enum kobject_action action)
 {
 	switch (action) {
 	case KOBJ_ADD:
 		return "add";
 	case KOBJ_REMOVE:
 		return "remove";
 	case KOBJ_CHANGE:
 		return "change";
 	case KOBJ_OFFLINE:
 		return "offline";
 	case KOBJ_ONLINE:
 		return "online";
 	default:
 		return NULL;
 	}
 }

 /**
  * kobject_uevent - notify userspace by ending an uevent
  *
  * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
  * @kobj: struct kobject that the action is happening to
  */
 void kobject_uevent(struct kobject *kobj, enum kobject_action action)
 {
 	char **envp;
 	char *buffer;
 	char *scratch;
 	const char *action_string;
 	const char *devpath = NULL;
 	const char *subsystem;
 	struct kobject *top_kobj;
 	struct kset *kset;
 	struct kset_uevent_ops *uevent_ops;
 	u64 seq;
 	char *seq_buff;
 	int i = 0;
 	int retval;

 	pr_debug("%s\n", __FUNCTION__);

 	action_string = action_to_string(action);
 	if (!action_string)
 		return;

 	/* search the kset we belong to */
 	top_kobj = kobj;
 	if (!top_kobj->kset && top_kobj->parent) {
 		do {
 			top_kobj = top_kobj->parent;
 		} while (!top_kobj->kset && top_kobj->parent);
 	}
 	if (!top_kobj->kset)
 		return;

 	kset = top_kobj->kset;
 	uevent_ops = kset->uevent_ops;

 	/*  skip the event, if the filter returns zero. */
 	if (uevent_ops && uevent_ops->filter)
 		if (!uevent_ops->filter(kset, kobj))
 			return;

 	/* environment index */
 	envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
 	if (!envp)
 		return;

 	/* environment values */
 	buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
 	if (!buffer)
 		goto exit;

 	/* complete object path */
 	devpath = kobject_get_path(kobj, GFP_KERNEL);
 	if (!devpath)
 		goto exit;

 	/* originating subsystem */
 	if (uevent_ops && uevent_ops->name)
 		subsystem = uevent_ops->name(kset, kobj);
 	else
 		subsystem = kobject_name(&kset->kobj);

 	/* event environemnt for helper process only */
 	envp[i++] = "HOME=/";
 	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";

 	/* default keys */
 	scratch = buffer;
 	envp [i++] = scratch;
 	scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
 	envp [i++] = scratch;
 	scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
 	envp [i++] = scratch;
 	scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;

 	/* just reserve the space, overwrite it after kset call has returned */
 	envp[i++] = seq_buff = scratch;
 	scratch += strlen("SEQNUM=18446744073709551616") + 1;

 	/* let the kset specific function add its stuff */
 	if (uevent_ops && uevent_ops->uevent) {
 		retval = uevent_ops->uevent(kset, kobj,
 				  &envp[i], NUM_ENVP - i, scratch,
 				  BUFFER_SIZE - (scratch - buffer));
 		if (retval) {
 			pr_debug ("%s - uevent() returned %d\n",
 				  __FUNCTION__, retval);
 			goto exit;
 		}
 	}

 	/* we will send an event, request a new sequence number */
 	spin_lock(&sequence_lock);
 	seq = ++uevent_seqnum;
 	spin_unlock(&sequence_lock);
 	sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);

 	/* send netlink message */
 	if (uevent_sock) {
 		struct sk_buff *skb;
 		size_t len;

 		/* allocate message with the maximum possible size */
 		len = strlen(action_string) + strlen(devpath) + 2;
 		skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
 		if (skb) {
 			/* add header */
 			scratch = skb_put(skb, len);
 			sprintf(scratch, "%s@%s", action_string, devpath);

 			/* copy keys to our continuous event payload buffer */
 			for (i = 2; envp[i]; i++) {
 				len = strlen(envp[i]) + 1;
 				scratch = skb_put(skb, len);
 				strcpy(scratch, envp[i]);
 			}

 			NETLINK_CB(skb).dst_group = 1;
 			netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
 		}
 	}

 	/* call uevent_helper, usually only enabled during early boot */
 	if (uevent_helper[0]) {
 		char *argv [3];

 		argv [0] = uevent_helper;
 		argv [1] = (char *)subsystem;
 		argv [2] = NULL;
 		call_usermodehelper (argv[0], argv, envp, 0);
 	}

 exit:
 	kfree(devpath);
 	kfree(buffer);
 	kfree(envp);
 	return;
 }
 EXPORT_SYMBOL_GPL(kobject_uevent);

 /**
  * add_uevent_var - helper for creating event variables
  * @envp: Pointer to table of environment variables, as passed into
  * uevent() method.
  * @num_envp: Number of environment variable slots available, as
  * passed into uevent() method.
  * @cur_index: Pointer to current index into @envp.  It should be
  * initialized to 0 before the first call to add_uevent_var(),
  * and will be incremented on success.
  * @buffer: Pointer to buffer for environment variables, as passed
  * into uevent() method.
  * @buffer_size: Length of @buffer, as passed into uevent() method.
  * @cur_len: Pointer to current length of space used in @buffer.
  * Should be initialized to 0 before the first call to
  * add_uevent_var(), and will be incremented on success.
  * @format: Format for creating environment variable (of the form
  * "XXX=%x") for snprintf().
  *
  * Returns 0 if environment variable was added successfully or -ENOMEM
  * if no space was available.
  */
 int add_uevent_var(char **envp, int num_envp, int *cur_index,
 		   char *buffer, int buffer_size, int *cur_len,
 		   const char *format, ...)
 {
 	va_list args;

 	/*
 	 * We check against num_envp - 1 to make sure there is at
 	 * least one slot left after we return, since kobject_uevent()
 	 * needs to set the last slot to NULL.
 	 */
 	if (*cur_index >= num_envp - 1)
 		return -ENOMEM;

 	envp[*cur_index] = buffer + *cur_len;

 	va_start(args, format);
 	*cur_len += vsnprintf(envp[*cur_index],
 			      max(buffer_size - *cur_len, 0),
 			      format, args) + 1;
 	va_end(args);

 	if (*cur_len > buffer_size)
 		return -ENOMEM;

 	(*cur_index)++;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(add_uevent_var);

 static int __init kobject_uevent_init(void)
 {
 	uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
 					    THIS_MODULE);

 	if (!uevent_sock) {
 		printk(KERN_ERR
 		       "kobject_uevent: unable to create netlink socket!\n");
 		return -ENODEV;
 	}

 	return 0;
 }

 postcore_initcall(kobject_uevent_init);

 #endif /* CONFIG_HOTPLUG */
	/*
	* kernel userspace event delivery
	*
	* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
	* Copyright (C) 2004 Novell, Inc. All rights reserved.
	* Copyright (C) 2004 IBM, Inc. All rights reserved.
	*
	* Licensed under the GNU GPL v2.
	*
	* Authors:
	* Robert Love <rml@novell.com>
	* Kay Sievers <kay.sievers@vrfy.org>
	* Arjan van de Ven <arjanv@redhat.com>
	* Greg Kroah-Hartman <greg@kroah.com>
	*/

	#include <linux/spinlock.h>
	#include <linux/socket.h>
	#include <linux/skbuff.h>
	#include <linux/netlink.h>
	#include <linux/string.h>
	#include <linux/kobject.h>
	#include <net/sock.h>

	#define BUFFER_SIZE 2048 /* buffer for the variables */
	#define NUM_ENVP 32 /* number of env pointers */

	#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
	static DEFINE_SPINLOCK(sequence_lock);
	static struct sock *uevent_sock;

	static char *action_to_string(enum kobject_action action)
	{
	switch (action) {
	case KOBJ_ADD:
	return "add";
	case KOBJ_REMOVE:
	return "remove";
	case KOBJ_CHANGE:
	return "change";
	case KOBJ_OFFLINE:
	return "offline";
	case KOBJ_ONLINE:
	return "online";
	default:
	return NULL;
	}
	}

	/**
	* kobject_uevent - notify userspace by ending an uevent
	*
	* @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
	* @kobj: struct kobject that the action is happening to
	*/
	void kobject_uevent(struct kobject *kobj, enum kobject_action action)
	{
	char **envp;
	char *buffer;
	char *scratch;
	const char *action_string;
	const char *devpath = NULL;
	const char *subsystem;
	struct kobject *top_kobj;
	struct kset *kset;
	struct kset_uevent_ops *uevent_ops;
	u64 seq;
	char *seq_buff;
	int i = 0;
	int retval;

	pr_debug("%s\n", __FUNCTION__);

	action_string = action_to_string(action);
	if (!action_string)
	return;

	/* search the kset we belong to */
	top_kobj = kobj;
	if (!top_kobj->kset && top_kobj->parent) {
	do {
	top_kobj = top_kobj->parent;
	} while (!top_kobj->kset && top_kobj->parent);
	}
	if (!top_kobj->kset)
	return;

	kset = top_kobj->kset;
	uevent_ops = kset->uevent_ops;

	/* skip the event, if the filter returns zero. */
	if (uevent_ops && uevent_ops->filter)
	if (!uevent_ops->filter(kset, kobj))
	return;

	/* environment index */
	envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
	if (!envp)
	return;

	/* environment values */
	buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
	if (!buffer)
	goto exit;

	/* complete object path */
	devpath = kobject_get_path(kobj, GFP_KERNEL);
	if (!devpath)
	goto exit;

	/* originating subsystem */
	if (uevent_ops && uevent_ops->name)
	subsystem = uevent_ops->name(kset, kobj);
	else
	subsystem = kobject_name(&kset->kobj);

	/* event environemnt for helper process only */
	envp[i++] = "HOME=/";
	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";

	/* default keys */
	scratch = buffer;
	envp [i++] = scratch;
	scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
	envp [i++] = scratch;
	scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
	envp [i++] = scratch;
	scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;

	/* just reserve the space, overwrite it after kset call has returned */
	envp[i++] = seq_buff = scratch;
	scratch += strlen("SEQNUM=18446744073709551616") + 1;

	/* let the kset specific function add its stuff */
	if (uevent_ops && uevent_ops->uevent) {
	retval = uevent_ops->uevent(kset, kobj,
	&envp[i], NUM_ENVP - i, scratch,
	BUFFER_SIZE - (scratch - buffer));
	if (retval) {
	pr_debug ("%s - uevent() returned %d\n",
	__FUNCTION__, retval);
	goto exit;
	}
	}

	/* we will send an event, request a new sequence number */
	spin_lock(&sequence_lock);
	seq = ++uevent_seqnum;
	spin_unlock(&sequence_lock);
	sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);

	/* send netlink message */
	if (uevent_sock) {
	struct sk_buff *skb;
	size_t len;

	/* allocate message with the maximum possible size */
	len = strlen(action_string) + strlen(devpath) + 2;
	skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
	if (skb) {
	/* add header */
	scratch = skb_put(skb, len);
	sprintf(scratch, "%s@%s", action_string, devpath);

	/* copy keys to our continuous event payload buffer */
	for (i = 2; envp[i]; i++) {
	len = strlen(envp[i]) + 1;
	scratch = skb_put(skb, len);
	strcpy(scratch, envp[i]);
	}

	NETLINK_CB(skb).dst_group = 1;
	netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
	}
	}

	/* call uevent_helper, usually only enabled during early boot */
	if (uevent_helper[0]) {
	char *argv [3];

	argv [0] = uevent_helper;
	argv [1] = (char *)subsystem;
	argv [2] = NULL;
	call_usermodehelper (argv[0], argv, envp, 0);
	}

	exit:
	kfree(devpath);
	kfree(buffer);
	kfree(envp);
	return;
	}
	EXPORT_SYMBOL_GPL(kobject_uevent);

	/**
	* add_uevent_var - helper for creating event variables
	* @envp: Pointer to table of environment variables, as passed into
	* uevent() method.
	* @num_envp: Number of environment variable slots available, as
	* passed into uevent() method.
	* @cur_index: Pointer to current index into @envp. It should be
	* initialized to 0 before the first call to add_uevent_var(),
	* and will be incremented on success.
	* @buffer: Pointer to buffer for environment variables, as passed
	* into uevent() method.
	* @buffer_size: Length of @buffer, as passed into uevent() method.
	* @cur_len: Pointer to current length of space used in @buffer.
	* Should be initialized to 0 before the first call to
	* add_uevent_var(), and will be incremented on success.
	* @format: Format for creating environment variable (of the form
	* "XXX=%x") for snprintf().
	*
	* Returns 0 if environment variable was added successfully or -ENOMEM
	* if no space was available.
	*/
	int add_uevent_var(char *envp, int num_envp, int cur_index,
	char buffer, int buffer_size, int cur_len,
	const char *format, ...)
	{
	va_list args;

	/*
	* We check against num_envp - 1 to make sure there is at
	* least one slot left after we return, since kobject_uevent()
	* needs to set the last slot to NULL.
	*/
	if (*cur_index >= num_envp - 1)
	return -ENOMEM;

	envp[cur_index] = buffer + cur_len;

	va_start(args, format);
	cur_len += vsnprintf(envp[cur_index],
	max(buffer_size - *cur_len, 0),
	format, args) + 1;
	va_end(args);

	if (*cur_len > buffer_size)
	return -ENOMEM;

	(*cur_index)++;
	return 0;
	}
	EXPORT_SYMBOL_GPL(add_uevent_var);

	static int __init kobject_uevent_init(void)
	{
	uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
	THIS_MODULE);

	if (!uevent_sock) {
	printk(KERN_ERR
	"kobject_uevent: unable to create netlink socket!\n");
	return -ENODEV;
	}

	return 0;
	}

	postcore_initcall(kobject_uevent_init);

	#endif /* CONFIG_HOTPLUG */